2 May 2022

A recent preprint (arxiv link 2202.07501) with Mehdi Drissi (currently at TRIUMF) has just been published at the European Journal of Physics A (link here). In this paper, we took a critical look at the pairing critical temperature in neutron matter. We show that some approximations for superfluidity predict ratios of the critical temperature to the zero-temperature gap that are different from the BCS prediction. The ratios are relatively independent of the nuclear force that is employed, and the values agree with predictions for ultracold gases. This may have implications for neutron-star cooling simulations!

In a just-published paper in Phys Rev C here (arxiv link 2001.07231) with colleagues at Washington University in St Louis and Argonne National Laboratory, we have critically looked at the saturation energy of infinite nuclear matter. Using 3 different theoretical methods, we conclude that it is possible for this energy to deviate from the canonical value of E=-16 MeV. Finite nuclei fits of the dispersive optical model suggests it could be as low as E=-13 MeV, which could have important consequences for a variety of nuclear phenomena.

I have published a short review on self-consistent Green's functions methods and their potential in the study of infinite matter here (arxiv link 2006.10610). I tried to highlight the advantages of this approach, which yields a broad range of information in a single simulations. We can predict the equation of state (of interest for neutron stars), but also get the in-medium spectral strength of nucleons (see contour plot here!).

My PhD student James Keeble has solved a nuclear physics problem using machine learning techniques! Using the ready-made PyTorch suite, he has been able to find the ground state of the deuteron (the only bound state of a neutron and a proton) with extreme accuracy using a very simple artificial neural network as a wavefunction. We think this paves the way for new techniques of nuclear many-body based on machine learning. Find out more in our preprint here 1911.13092 and watch this space for further updates!

The Hellmann-Feynman theorem is a key result in quantum mechanics that is used across disciplines, from quantum chemistry to particle physics. In my latest preprint at arxiv:1909.10298 (now published in the American Journal of Physics), I worked with collaborators at Barcelona and Catania and looked at the extension of the theorem to finite temperatures. We applies the theorem to 3 very different quantum mechanical systems, hoping that this analysis can potentially be used in quantum mechanics or statistical mechanics teaching. 

From 24 to 26 July 2019, I co-organised with colleagues at Surrey a workshop on Ab Initio Nuclear Theory. Researchers from around the world came to Guildford to discuss the most recent breakthroughs in nuclear theory, which have allowed for a real explosion of first-principles predictions. We asked ourselves the question what next in ab initio theory? and had fun trying to answer it!